The present disclosure relates in general to water and thermal management of fuel cell power plants, and more particularly, to a system and method for recovering water and electrolyte from an exhaust stream of a fuel cell using a corrosion resistant membrane condenser.
In the operation of a fuel cell, air or other oxidant is pumped in high volume through the cathode side of the fuel cell. In passing the cathode, the oxidant is depleted and water vapor is picked up by the oxidant depleted air and transported away from the cathode in a cathode exhaust stream. A substantial amount of electrolyte vapor is also dragged out of the fuel cell with the cathode exhaust stream because of the high operating temperature of the fuel cell which tends to vaporize the electrolyte. For example, phosphoric acid fuel cells are typically run at 400° F. (204° C.), producing phosphoric acid vapors. The recovery of the water vapor from the cathode exhaust stream is desirable because the water can then be recycled for uses including, for example, humidifying the fuel cell inlet gases, performing evaporative cooling of inlet gases, or supplying water for a steam reformer. However, if the phosphoric acid or other electrolyte is recovered with the water, it can become unusable for steam reforming purposes and can be corrosive to water condensing systems, thus shortening system life and requiring costly replacement of components.